Pressure control



Ap 2, 1940. g. A. OTTO PRESSURE CONTROL Filed June 7, 1939 2Sheets-Sheet 1 ane MAIN/VB (Ittornegs Patented Apr. I

UNITED STATES PATENT OFFi PRESSURE CONTROL CiltlA. om, Milwaukee, Wis.,assignor to mm.

son Service Company, Milwaukee, ,Wis., a corporation of WisconsinApplication June 7, 1939, Serial No. 277,963

'1 Claims. (01. 137-153 This invention relates to pressure regulatorsintended to respond to static pressure in an air.-

the effect is to disturb the distribution and to an- 15 extent to defeatthe regulatory action of those controls which are supposed to regulatetemperature or humidity, or both, in the conditioned space.

The present invention produces an extremely sensitive device which noOnly responds to pressure. in'the duct but responds to" the diflerentialbetween that pressure and atmospheric pressure.

The device is so sensitive that it will respond to pressure variationsof the order of 0.01 inch of 5 water. and within a very small pressurerange serves to operate a controlled mechanism such as f a damper motorthroughout its entire range. The invention offers simple means foradjusting or zeroing the control point of the instrument and 30 alsoprovides means for readjusting and changing this control point bygraduated amounts from a remote point. The amount of the change soefiected is also capable of ready adjustment at the instrument.

35 A commercial embodiment of the invention will now be described withreference to the accompanying drawings in which Figure 1 is a frontelevation of the complete device with the cover removed to disclose theinternal construction, the instrument being shown diagrammaticallyconnected in a control system to which it is suited.

Figure 2 is a plan view of the control instrument shown in Figure 1withthe cover in place and partly broken away to illustrate the internalconstruction.

Figure 3 is a section on line 3-3 of Figure 2 looking to the right withreference to that fl'gure.

Figure 4 is a section on the line 4-4 of Figure 5 1 looking to the leftwith reference to that figure. Figure 5 is a fragmentary viewillustrating how the re-adjusting mechanism may be set variably, tomodify the degree of re-adjustment.

A panel on which the control mechanism is 5 mounted is shown at 6, and Iindicates an intermediate reverse acting pneumatic relay of the typedescribed and claimed in the patent to Otto, i

.No. 1,726,409, August 27, 1929 is mounted on the panel 6, immediatelyabove the control instrument forming the subject matter of the 6 presentapplication.

A. base casting 8 of generally circular form with mounting lugs 9 andamating cap casting H receive between them a sensitive flexiblediaphragm I2. The two castings are connected by a plurality 101 ofscrews I3 and the periphery of the diaphragm is sealed tightly by themarginal portions of the two castings. In this way two isolated chambersl4, iii, are provided. Clamped through the center of the diaphragm I!are stiffener plates I 6 "T which are flared at their'edges as shown. 1

Attached to the plates 16 is a stem H which projects forward and isclamped by nuts 18 to the center of asmall circularly corrugateddiaphragm I9. The diaphragm I9 is sealed between a flange 20 2| on thecasting ll and a cap plate 22 .whi'ch isattached by screws to thatflange. The diaphragm I9 is of. negligible'area as compared to thediaphragm l2 and serves merely as a packless gland serving to sealth'efchamber l5. The chamber H to the rear of the diaphragm" H isconnected byf'atube 23 and orifice 24 to the interior of a duct 25' inwhich duct the pressure is to be sensed by the instrument. The chamberl5 forward of the diaphragm l2 isirnaintainedv at atmospheric pressureand to avoid any disturbing pressure effectswhich mightexist within thebuilding, thechamb'er I5 is connected by the tube 26 to a point outsidethe building. To bring about this result, the tube leads through theoutside wall conventionally indicated at 21. Theorifice 24 is so locatedthat it is subject to static pressure in the duct andis not affected byvelocity of air flow in the duct. To secure this result the orifice 24is in a plane face parallel; 40

with the path of flow. Thus, the diaphragm responds to the pressuredifferential between the interior; of the duct and the outside,atmosphere which, as is well-known, is a variable pressure. Accordingt'othe embodiment here described .the ,45

'duct 25 is at a pressure which is alway's ll'i" her than atmospheric;Consequently, the diaph gm, is loaded in opposition toduct pressure"that is,

urged to the right as viewed in a coiled compression spring 28 which? 9tween one o'f'the plates l6 and a spring seat 29."-

As best-shown in Figure 2, the'spring seat 29 is carried by the end of alever 3| which is pivoted on pivot screws 32 within an enlargement ofchamber 15 formed in casting ll to the right of flange 2|. The positionof the lever is adjusted 7 an approximately vertical lever 36 which ispivoted at 31 to the brackets 38 and which is urged to swing in aclockwise direction as viewed in Figure 4 by a small weight 39. In thisway, the

its functions are as follows:

- branch line 48 leading from the relay is subject to 4 lever is kept incontact with the stem without exerting any material thrust upon thatstem. Such thrust as is exerted'is virtually constant. Lever 34 is inthrust engagement with a pendant lever 4| which is pivoted at '42 on abracket 43. The lever 41 is urged by gravity to swing in acounter-clockwise direction and since the two levers 34 and 4| arereversely arranged, the thrust member 44 which is longitudinallyadjustable on the lever 4| aflords a variable ratio drive connectionbetween the two levers. 3 The adjustable thrust member 44 isfrictionally clamped upon the lever 4| and may he slid up and downbetween the limits imposed by the length of the lever 34. The lever 4|carries a pad or valve element 45 which coacts with a leak-port 46 tocontrol the relay 1. The leak-port 46 corre- .sponds to; and isfunctionallyidentical with the leak-port 51 in the Otto Patent No.1,726,409.

In so far as is material tothe present invention,

-' Supply air line 41 delivers air to the relay '1 'under pressure of(say) fifteen pounds gauge,

that'being the standard pressure in this art. The

pressure control by the relay in such manner that when the leak-port 44is wide open, the pressure in the branch line 44 equals the pressure. inthe supply line 41, in this case, fifteen pounds gauge. Conversely, whenthe leak-port 46 is sealed by the valve 45, the pressure in the branchline 48 is zero pounds, that is, the line is at atmospheric pressure.The branch line 48 leads to a damper motor 40 which is a bellows motorconnected to turn the lever 5i clockwise about its pivot 52 in responsej to rising pressure in the pipe 48. Such motion is resisted by a-returnspring 53.

The lever 52 is connected by a link 54 and crank 55 with a multiplelouvered damper 58 of conventional form, so that rising branch linepressure causes thedamper to move in a closing direction.

The parts are so arranged that as pressure in the duct 25 rises, thediaphragm I2 will be moved to the left tending to open the leak-port 46.The opening of the leak-port 46. causes (through the action of therelay 1) an increase of pressure in the branch line 48. This causes thelever 5| to turn clockwise thus closing the damper 58. The action isgradual because the motion of the diaphragm I2 is gradual, the relay 1is of the gradual or progressively acting type and the damper motormoves proportionally to pressure in the'branch line 44.,

clamped between the nuts 4| on the outer end of the stem ll.

To render the spring I! effective, it is stressed by exerting thrustupon the boss 62. To exert such stress, use is made of a pressure motormechanism which will now be described.

A bracket 43 mounted on the casting H affords pivot bearings 44 forplate-like lever 65. This lever, as viewed in Figure 1 is swungclockwise by two coil tension springs 46. The springs are not connecteddirectly to the lever 45 but are connected to the ends of secondarylevers 41 which are pivoted at 68 to lever and are adjustable relativelythereto by turning thrust screws 4l.

The lever 65 may be. forced counter-clockwise by a metal cell diaphragmII, which is mounted on a boss 12 and which'bears at its left-hand faceon the lever 65. A loading line 13 is connected by a port 14 to theinterior of the diaphragm H.

Pressure in line 13 is controlled by a gradual switch 15 which is simplya manually adjustable pressure reducing valve supplied with air by line41.

When the diaphragm II is under pressure, lever 65 swingscounter-clockwise. It carries at its upper end plate 18. Pivoted at TIto the plate 14 is a lever 18 having a straight cam nose I! in positionto coact with the boss 62. The a'ngularity of ,the cam'n'ose ll-may beadjusted by shifting the extent of adjustment of the spring 61 effectedby the full range of motion of lever 65 is determined by changing theobliquity of the cam face 19.

The adjustment mechanism just described, can be used for variouspurposes. The adjustment is progressive. Lever 65 starts to move at onepound pressures in line 13 and completes its motion at fifteen pounds.

While one embodiment of the invention has been described in considerabledetail, the description is intended to be illustrative and not limiting.The scope of the invention will be defined in the claims.

What is claimed is: 1. Means for actuating a leak'controlling valveaccording to variations in a controlling pressure which comprises, adiaphragm; means for subjecting said diaphragm on opposite sides to saidcontrolling pressure and to atmospheric pressure a leak controllingvalve; an actuating connection between said diaphragm and valve;yielding .means for loading said diaphragm; means local to theinstrument for adjusting said loading means; a pressure motor arrangedto develop a load modifying force; and pressure controlling meansoperable at a point remote from said instrument to vary the pressure insaid motor means. v

2. Means for actuating a leak controlling valve according to variationsin a controlling pressure which comprises, a diaphragm; meansfor'subpressure controlling means operable at a point remote from saidinstrument to vary the pressure in said motor means.

3. Means for actuating a leak controlling valve according to variationsin a controlling pressure which comprises, a diaphragm; means forsubjecting said diaphragm on opposite sides to said controlling pressureand to atmospheric pres sure; a leak controlling valve; an actuatingconnection between said diaphragm and valve; yielding means for loadingsaid diaphragm; means local to the instrument for adjusting said loadingmeans; a pressure motor arranged to develop a load modifying force;pressure controlling means operable at a point remote from saidinstrument to vary the pressure in said motor means; and means local tothe instrument for arying the ratio between the pressure in said motorand the load modifying force developed thereby.

4. Means for actuating a leak controlling valve according to variationsin a controlling pressure which comprises, a diaphragm; means forsubjecting said diaphragm on opposite sides tosaid controlling pressureand to atmospheric pressure; a leak controlling valve; an actuatingconnection between said diaphragm and valve; ratio changing meansassociated with said connection to vary the motion ratio of thediaphragm and valve; yielding means for loading said diaphragm; meanslocal to the instrument for adlusting said loading means; apressuremotor arranged to develop a load modifying force; pressurecontrolling means operable at a point remote from said instrument tovary the pressure in said motor means; and means local to the instrumentfor varying the ratio between the pressure in said motor and the loadmodifying force developed thereby.

5. Means for actuating a leak controlling valve according to variationsin the pressure difierential between two fluid pressures whichcomprises, a flexible diaphragm; means for subjecting said diaphragm onopposite sides to respective fluid pressures; a leak controlling valve;a variable ratio actuating connection between said diaphragm and valve;a primary loading spring reacting against said diaphragm; means 10- calto the instrument for adjusting the stress on said spring; a secondaryloading spring; a pressure motor for developing stress on said secondaryloading spring; and pressure controlling means operable from a remotepoint and serving to vary the pressure in said motor.

6. Means for actuating a leak controlling valve according to variationsin the pressure differential between two fluid pressures whichcomprises, a flexible diaphragm; means for subjecting said diaphragm onopposite sides to respective fluid pressures; a leak controlling valve;a variable ratio actuating connection between said diaphragm and valve;a primary loading spring reacting against said diaphragm; means 10- calto the instrument for adjusting the stress on said spring; a secondaryloading spring; a pressure motor for developing stress on said secondaryloading spring; pressure controlling means operable from a remote pointand serving to vary the pressure in said motor; and means local to theinstrument for varying the ratio between the pressure in said motor andthe stress developed by the motor on said secondary loading spring.

7. The combination defined in claim 6 in which the secondary loadingspring is a leaf spring supported at one end and connected at its otherend with said diaphragm and the pressure motor means operates to deflectsaid leaf spring at a point intermediate its ends.

' CARL A. OTTO.

